Cam Grooving Machine

ABSTRACT

A device for cold working pipe elements has two or more cams, each having a gear which meshes with a pinion to turn all of the cams. Each cam has a cam surface with a region of increasing radius and may have a region of constant radius extending around a cam body. Each cam also has a traction surface extending around a cam body. A region of reduced radius in each cam surface is aligned with a gap in the traction surface of each cam. The regions of reduced radius and gaps provide clearance for insertion and removal of the pipe element between the cams to form a circumferential groove when the cams are rotated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to and is a continuation ofU.S. application Ser. No. 17/500,433, filed Oct. 13, 2021, whichapplication claims benefit of priority to and is a continuation of U.S.application Ser. No. 16/677,708, filed Nov. 8, 2019, which applicationclaims benefit of priority to and is a continuation of U.S. applicationSer. No. 15/358,475, filed Nov. 22, 2016, now U.S. Pat. No. 10,525,517,issued Jan. 7, 2020, which application is based upon and claims benefitof priority to U.S. Provisional Application No. 62,260,922, filed Nov.30, 2015; U.S. Provisional Application No. 62/359,395, filed Jul. 7,2016; U.S. Provisional Application No. 62/363,892, filed Jul. 19, 2016;and U.S. Provisional Application No. 62/395,747, filed Sep. 16, 2016,all aforementioned applications being hereby incorporated by referenceherein.

FIELD OF THE INVENTION

This invention relates to machines using cams to cold work pipeelements.

BACKGROUND

Cold working of pipe elements, for example, impressing a circumferentialgroove in a pipe element to accept a mechanical pipe coupling, isadvantageously accomplished using roll grooving machines having an innerroller which engages an inside surface of the pipe element and an outerroller which simultaneously engages an outside surface of the pipeelement opposite to the inner roller. As the pipe is rotated about itslongitudinal axis, often by driving the inner roller, the outer rolleris progressively forced toward the inner roller. The rollers havesurface profiles which are impressed onto the pipe element circumferenceas it rotates, thereby forming a circumferential groove.

There are various challenges which this technique faces if it is to coldwork pipe elements with the required tolerances to the necessaryprecision. Most pressing are the difficulties associated with producinga groove of the desired radius (measured from the center of the pipeelement bore to the floor of the groove) within a desired tolerancerange. These considerations have resulted in complicated prior artdevices which, for example, require actuators for forcing the rollersinto engagement with the pipe element and the ability for the operatorto adjust the roller travel to achieve the desired groove radius.Additionally, prior art roll grooving machines have low productionrates, often requiring many revolutions of the pipe element to achieve afinished circumferential groove. There is clearly a need for devices,for example, those using cams, to cold work pipe elements which aresimple yet produce results with less operator involvement.

SUMMARY

The invention concerns a cam for cold working a pipe element. In oneexample embodiment the cam comprises a cam body having an axis ofrotation. A cam surface extends around the cam body. The cam surfacecomprises a region of increasing radius and a region of reduced radius.By way of example, the region of reduced radius may comprise adiscontinuity of the cam surface. The cam surface may also comprise aregion of constant radius positioned adjacent to the region of reducedradius. A traction surface may extend around the cam body. The tractionsurface comprises a plurality of projections extending transversely tothe axis of rotation. The traction surface has a gap therein. The gap isaligned axially with the region of reduced radius of the cam surface. Inone example embodiment the traction surface overlies the cam surface. Inanother example embodiment the traction surface is positioned on the cambody in spaced relation to the cam surface. By way of example, the camfurther comprises a gear mounted on the cam body coaxially with the axisof rotation. In one example embodiment the cam surface is positionedbetween the gear and the traction surface. Further by way of example thecam surface is positioned proximate to the traction surface. In anexample embodiment the traction surface has a constant radius measuredabout and from the axis of rotation.

In a further example embodiment the cam comprises a cam body having anaxis of rotation. A plurality of cam surfaces extend around the cambody. Each cam surface comprises a respective region of increasingradius. Each cam surface may also comprise a respective region ofconstant radius. The radii are measured from and about the axis ofrotation. All of the cam surfaces are circumferentially aligned with oneanother. Respective regions of reduced radius of the cam surfaces arepositioned between each of the cam surfaces.

In an example embodiment the cams may further comprise a plurality oftraction surfaces extending around the cam body. Each traction surfacecomprises a plurality of projections extending transversely to the axisof rotation. A respective gap in the traction surfaces is positionedbetween each of the traction surfaces. Each gap is aligned axially witha respective region of reduced radius of the cam surface. In an exampleembodiment, all of the traction surfaces are circumferentially alignedwith one another. In a particular example, the traction surfaces overliethe cam surfaces. In another example, the traction surfaces arepositioned on the cam body in spaced relation to the cam surfaces.

By way of example, a cam further comprises a gear mounted on the cambody coaxially with the axis of rotation. In a specific example the camsurfaces are positioned between the gear and the traction surfaces. Inanother example the cam surfaces are positioned proximate to thetraction surfaces. A specific example embodiment comprises at most twoof the cam surfaces and two of the regions of reduced radius of the camsurfaces. Another example embodiment comprises at most two of the camsurfaces, two of the regions of reduced radius of the cam surfaces, twoof the traction surfaces and two of the gaps in the traction surfaces.

The invention further encompasses a device for cold working a pipeelement. In one example embodiment the device comprises a housing. Aplurality of gears are mounted within the housing. Each one of the gearsis rotatable about a respective one of a plurality of axes of rotation.The gears are positioned about a central space for receiving the pipeelement. A plurality of cam bodies are each mounted on a respective oneof the gears. Each one of a plurality of cam surfaces extend around arespective one of the cam bodies and are engageable with the pipeelement received within the central space. Each one of the cam surfacescomprises a region of increasing radius and a region of reduced radius.Each one of the cam surfaces may also comprise a region of constantradius positioned adjacent to the region of reduced radius. Each one ofthe radii is measured about and from a respective one of the axes ofrotation. At least one traction surface extends around one of the cambodies. The at least one traction surface comprises a plurality ofprojections extending transversely to the axis of rotation of the onecam body. The at least one traction surface has a gap therein. The gapis aligned axially with the region of reduced radius of one the camsurface surrounding the one cam body. A pinion is mounted within thecentral space within the housing. The pinion meshes with the pluralityof gears and is rotatable about a pinion axis.

Another example embodiment comprises a plurality of traction surfaces.Each one of the traction surfaces extends around a respective one of thecam bodies. Each one of the traction surfaces comprises a plurality ofprojections extending transversely to a respective one of the axes ofrotation. Each one of the traction surfaces has a gap therein. Each gapis aligned axially with a respective one of the regions of reducedradius of one of the cam surfaces on each one of the cam bodies.

In an example embodiment the at least one traction surface overlies oneof the cam surfaces. In another example embodiment the at least onetraction surface is positioned on the one cam body in spaced relation tothe cam surface extending around the one cam body. By way of example adevice may comprise at most, three gears. Each gear comprises one of thecam bodies and the cam surfaces. Another example embodiment may compriseat most, two gears. Each gear comprises one of the cam bodies and thecam surfaces.

In an example embodiment, the one cam surface is positioned between thegear and the at least one traction surface of the one cam body. by wayof further example, the one cam surface is positioned proximate to theat least one traction surface of the one cam body.

An example device may further comprise at least one projection attachedto the pinion. The at least one projection extends transversely to thepinion axis. At least one cut-out is defined by the housing. The atleast one cut-out is positioned in facing relation with the projection.The pinion is movable relatively to the housing along the pinion axisbetween a first position, wherein the projection engages the cut-outthereby preventing rotation of the pinion, and a second position,wherein the projection is out of engagement with the cut-out therebypermitting rotation of the pinion. In an example embodiment a springacts between the pinion and the housing to bias the pinion into thefirst position.

An example embodiment further comprises a cup abutting the pinion. Thecup receives the pipe element upon insertion of the pipe element intothe central space. In one example embodiment the cup may be attached tothe pinion.

By way of further example, a first finger extends from a first one ofthe cam bodies in a direction offset from a first one of the axes ofrotation about which the first one of the cam bodies rotates. Anactuator is movably mounted on the housing. The actuator is movable intoengagement with the first finger for rotating the first one of the cambodies about the first one of the axes of rotation. In an exampleembodiment the actuator comprises a lever pivotably mounted on thehousing. The lever has a first surface engageable with the first fingerfor rotating the first one of the cam bodies about the first one of theaxes. In a further example the lever has a second surface engageablewith the finger for pivoting the lever into a ready position uponrotation of the first one of the cam bodies. In another example a secondfinger extends from a second one of the cam bodies in a direction offsetfrom a second one of the axes of rotation about which the second one ofthe cam bodies rotates. A stop is movably mounted on the housing. Thestop is movable into engagement with the second finger for preventingrotation of the second one of the cam bodies about the second one of theaxes of rotation. Upon movement of the actuator into engagement with thefirst finger, the stop further is movable out of engagement with thesecond finger for permitting rotation of the second one of the cambodies.

In one example embodiment the stop comprises a hook pivotably mounted onthe housing. The hook has a spur extending therefrom and is engageablewith the actuator for rotating the hook out of engagement with thesecond finger upon movement of the actuator.

An example device further comprises a chuck for receiving the pipeelement. The chuck is rotatable about a chuck axis. The chuck axis isarranged coaxially with the pinion axis. By way of example the housingis pivotably and slidably mounted adjacent to the chuck. In an exampleembodiment the device further comprises an electrical motor engaged withthe pinion. In a specific example embodiment the electrical motorcomprises a servomotor. The device further comprises a controller incommunication with the servomotor for controlling the number ofrotations of the servomotor and thereby the cam bodies.

Another example embodiment comprises a clutch operating between theelectrical motor and the pinion for controlling the number of rotationsof the pinion and thereby the cam bodies. A further example embodimentcomprises a crank coupled with the pinion. The crank permitting manualturning of the pinion and thereby the gears. In a particular exampleembodiment the crank is directly coupled with the pinion.

The invention further encompasses an example device for cold working apipe element comprising a housing. A plurality of gears are mountedwithin the housing. Each one of the gears is rotatable about arespective one of a plurality of axes of rotation. The gears arepositioned about a central space for receiving the pipe element. Theexample device has a plurality of cam bodies, each cam body is mountedon a respective one of the gears. A plurality of cam surfaces extendaround each cam body. Each cam surface is engageable with the pipeelement received within the central space and comprises a region ofincreasing radius and a region of constant radius. The radii aremeasured about and from one of the axes of rotation. All of the camsurfaces on each cam body are circumferentially aligned with oneanother. A respective region of reduced radius of the cam surfaces ispositioned between each of the cam surfaces on each the cam body. Apinion is mounted within the central space within the housing. Thepinion meshes with the plurality of gears and is rotatable about apinion axis.

Another example embodiment further comprises a plurality of tractionsurfaces extending around each the cam body. Each traction surfacecomprises a plurality of projections extending transversely to one ofthe axes of rotation. A respective gap in the traction surfaces ispositioned between each of the traction surfaces on each the cam body.Each gap is aligned axially with a region of reduced radius of the camsurface. By way of example the cam surfaces are positioned between thegear and the traction surfaces on each cam body. In a specific exampleembodiment the cam surfaces are positioned proximate to the tractionsurfaces on each the cam body. In another example embodiment, each ofthe cam bodies comprises at most two of the cam surfaces and two of theregions of reduced radius. By way of further example each of the cambodies comprises at most two of the cam surfaces, two of the regions ofreduced radius of the cam surfaces, two of the traction surfaces and twoof the gaps in the traction surfaces.

The invention also encompasses a method of forming a groove in a pipeelement. In one example embodiment the method comprises:

contacting the pipe element with a plurality of cam surfacessimultaneously at a plurality of locations on the pipe element;

rotating the pipe element, thereby simultaneously rotating the camsurfaces, each cam surface engaging the pipe element with an increasingradius and thereby deforming the pipe element to form the groove.

An example embodiment of the method further comprises contacting thepipe element with at least one traction surface mounted on at least onecam comprising one of the cam surfaces. Another example embodimentcomprising contacting the pipe element with a plurality of tractionsurfaces. In this example one the traction surface is mounted on arespective one of the cams. Each of the cams comprises one of theplurality of cam surfaces.

Another example embodiment comprises synchronizing rotation of the camsurfaces with one another. A further example embodiment comprises usingan actuator to initiate rotation of one of the cam surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an example embodiment of a deviceaccording to the invention;

FIG. 2 is an exploded isometric view of a portion of the device shown inFIG. 1 ;

FIG. 3 is an exploded isometric view of components of the device shownin FIG. 1 ;

FIG. 4 is an exploded isometric view of components of the device shownin FIG. 1 ;

FIG. 4A is an end view of an example cam according to the invention;

FIG. 4B is a side view of an example cam according to the invention;FIG. 4C is an isometric view of an example cam according to theinvention;

FIG. 5 is a cross sectional view of device 10 taken at line 5-5 of FIG.1 ;

FIGS. 6 through 9 and 9A are additional cross sectional viewsillustrating operation of device 10;

FIGS. 10-12 are cross sectional views illustrating a safe reverse modeof the device 10 when a pipe element is rotated in the wrong direction;

FIG. 13 is a partial view of another example embodiment of a deviceaccording to the invention;

FIG. 14 is an end view of another example cam according to theinvention;

FIGS. 15 and 16 are isometric views of example embodiments of devicesaccording to the invention; and

FIG. 17 is an isometric view of another example embodiment of a deviceaccording to the invention.

DETAILED DESCRIPTION

FIG. 1 shows an example device 10 for cold working a pipe element, forexample, forming a circumferential groove in the pipe element's outersurface. Device 10 is shown pivotably mounted on a rotating power chuck12. Such chucks are well known, an example being the Ridgid 300 PowerDrive marketed by Ridgid of Elyria, Ohio.

FIG. 2 shows an exploded view of device 10 which comprises a housing 14.Housing 14 is formed of a housing body 16 and a cover 18. A plurality ofgears, in this example three gears 20, 22 and 24 are rotatably mountedon respective shafts 26, 28 and 30, the shafts being supported by thehousing body 16 and cover 18 and defining respective axes of rotation32, 34 and 36. In a practical design each gear 20, 22 and 24 has arespective flanged bushing 38, and may also have a thrust washer 40 anda compression spring 42. The compression springs 42 act between thegears 20, 22 and 24 and the cover 18 to bias the gears away from thecover.

Gears 20, 22 and 24 are positioned about a central space 44 whichreceives a pipe element 136 to be cold worked by the device 10. Anopening 46 in cover 18 provides access to the central space 44 andpermits pipe element insertion into the device 10. As shown in FIGS. 2and 3 , a pinion 48 is mounted on housing body 16 within the centralspace 44. Pinion 48 meshes with gears 20, 22 and 24 and comprises apinion shaft 50 which defines a pinion axis of rotation 52. Pinion shaft50 is supported by a flanged pinion bushing 54 fixedly attached to thehousing body 16. In a practical design, a thrust bearing 56 and thrustwashers 58 are interposed between the pinion 48 and the housing body 16.

With reference to FIG. 3 , pinion 48 is movable relatively to housing 14in a direction along the pinion axis 52. A projection 60, in thisexample a crossbar 62 is attached to the pinion 48 and extendstransversely to the pinion axis 52. A cut-out 64, defined in the housingbody 16, is in facing relation with the projection 60 (crossbar 62). Inthis example, the cut-out 64 is in the pinion bushing 54 which isfixedly attached to and considered to be part of the housing body 16.Axial motion of the pinion 48 along pinion axis 52 moves the pinionbetween two positions, a first position wherein the crossbar 62(projection 60) engages the cut-out 64, and a second position whereinthe cross bar 62 is out of engagement with the cut-out 64. When crossbar62 engages the cut-out 64 the pinion 48 is prevented from rotating aboutthe pinion axis 52; when the cross bar 62 does not engage the cut-out 64the pinion 48 is free to rotate about the pinion axis 52. One or moresprings 66 act between the pinion 48 and the housing body 16 to bias thecrossbar 62 into the first position in engagement with the cut-out 64.Rotation of the pinion 48 is permitted when a pipe element 136 isinserted through opening 46 into the central space 44 (see FIG. 2 ) andheld against the pinion 48 to compress the springs 66 and disengage thecrossbar 62 from the cut-out 64. To provide contact between the pinion48 and the pipe element, a cup 68 abuts the pinion shaft 50 and iscaptured between the cam bodies. In a practical design the cup 68 may beattached to the pinion or free-wheeling. Cup 68 receives and maintainsthe pipe element in alignment with the pinion 48 so that it may beturned when cold working the pipe element as described below. Cup 68also helps limit pipe end flare during cold working.

As shown in FIG. 4 , device 10 comprises a plurality of cams 69, in thisexample, three cams having respective cam bodies 70, 72 and 74. Each cambody 70, 72 and 74 is mounted on a respective gear 20, 22 and 24. Eachcam body 70, 72 and 74 comprises a respective cam surface 76, 78 and 80.Each cam surface 76, 78 and 80 extends around their respective cam body70, 72 and 74. The cam surfaces 76, 78 and 80 are engageable with a pipeelement received within the central space 44.

As shown in detail in FIG. 4A, each one of the cam surfaces 76, 78, 80(76 shown) comprises a region 82 of increasing radius 82 a and a regionof reduced radius 86. In this example embodiment the region of reducedradius 86 comprises a discontinuity. Each one of the cam surfaces mayalso include a region 84 of constant radius 84 a positioned adjacent tothe region of reduced radius 86. The radii 82 a and 84 a (when present)are measured about and from the respective axes of rotation 32, 34 and36 of the gears 20, 22 and 24 (shown for the cam surface 76, the axis 32of gear 20). As shown in FIG. 5 , the regions of reduced radius 86, whenfacing the central space, provide clearance permitting insertion of thepipe element into the cup 68. With reference again to FIG. 4A, theexample device 10 has three cam bodies 70, 72 and 74. The regions ofconstant radius 84 extend along an arc length which is at least ⅓ of thecircumference of the finished circumferential groove in the pipe elementso that the groove may be formed to a uniform radius around the entirecircumference of the pipe element during one revolution of each cam body72, 74 and 76. In an example practical design (see FIG. 4A), the regionof increasing radius 82 may subtend an angle 88 of approximately 260°,and the region of constant radius (when present) may subtend an angle 90of approximately 78°, the region of reduced radius 86 subtending anangle 92 of approximately 22°. For devices 10 having a number of camsother than three and the constraint that the groove be formed to auniform radius around the entire circumference of the pipe element inone revolution of each of the cams, the arc length of the region ofconstant radius of each cam body is advantageously 1/N, where “N” is thenumber of cams in the design. However, it is feasible to reduce oreliminate entirely the region of constant radius. Elimination of thisregion will reduce the torque required to form the groove.

As shown in FIGS. 4 and 4B, it is advantageous to include at least onetraction surface 94 on one of the cam bodies such as 70. In the exampledevice 10 each cam body 70, 72 and 74 has a respective traction surface94, 96 and 98. The traction surfaces 94, 96 and 98 extendcircumferentially around their respective cam bodies 70, 72 and 74 andhave a constant radius measured about and from the respective axes ofrotation 32, 34 and 36. The cam surfaces 76, 78, 80, are positionedbetween the gears 20, 22 and 24 and the traction surfaces 94, 96 and 98,the cam surfaces being positioned proximate to the traction surfaces. Asshown in FIG. 4B, each traction surface (94 shown) comprises a pluralityof projections 100 which extend transversely to the respective axes ofrotation 32, 34 and 36. Projections 100 provide mechanical engagementand purchase between the cam bodies 70, 72 and 74 and the pipe elementwhich the traction surfaces engage. Each traction surface 94, 96 and 98also has a gap 102. Each gap 102 in each traction surface 94, 96 and 98substantially aligns axially with a respective region of reduced radius86 in each cam surface 76, 78, 80 to provide clearance permittinginsertion and withdrawal of the pipe element into and from the cup 68.In another cam embodiment 69a, shown in FIG. 4C, the traction surface 94overlies the cam surface 76. The gap 102 in the traction surface 94 isagain aligned with the region of reduced radius 86 in the cam surface76.

As shown in FIG. 5 , it is further advantageous to include an actuator106 to initiate motion of the cam bodies 70, 72 and 74. In this exampleembodiment, actuator 106 comprises an actuator lever 108 pivotablymounted on the housing body 16. Actuator lever 108 has a first surface110 which engages a finger 112 on cam body 74 to initiate rotation ofthe cam body. Finger 112 is offset from the axis of rotation 36 of cambody 74 (see also FIG. 2 ). The offset of finger 112 allows the actuatorlever 108, when pivoted about its pivot axis 108 a , to apply a torqueto the cam body 74 (gear 24) and rotate it about axis 36. This rotatesall of the cam bodies 70, 72 and 74 because their respective gears 20,22 and 24 mesh with the pinion 48, thus the act of turning any one gearor turning the pinion turns all gears. Actuator lever 108 also has asecond surface 114 which is engaged by the finger 112 as the cam body 74rotates. The second surface 114 is curved in this example and allows therotating cam body 74 to reset the relative positions of the finger 112and the actuator lever 108 so that upon one rotation of the cam body 74the actuator lever 108 is pivoted to a “ready” position as shown in FIG.6 , ready to apply a torque to the cam body and initiate rotation.

It is further advantageous to include a stop 116, movably mounted onhousing body 16 to prevent motion of the cam bodies. In this exampleembodiment, stop 116 comprises a hook 118 pivotably mounted on thehousing body 16 and has a pivot axis 118 a . Hook 118 engages a finger120 on cam body 70 (gear 20). Finger 120 is offset from the axis ofrotation 32 of cam body 70 (see also FIG. 2 ). The offset allows thehook 118 to arrest counter clockwise motion of cam body 70 as describedbelow. Tangent surfaces 122 and 124 are positioned at the end of hook118 for engagement with finger 120 during operation of the device asdescribed below. A torsion spring 126 (see also FIG. 2 ) acts betweenthe hook 118 and the housing body 16 to bias the hook in a counterclockwise direction around pivot axis 118 a . Hook 118 also has a spur128 which extends to the opposite side of the pivot axis 118 a from thehook (see also FIGS. 2 and 4 ). Actuator lever 108 has a foot 130 whichengages spur 128 to pivot the hook 118 out of engagement with finger 120upon movement of the actuator lever 108 into engagement with the finger112, forcing the cam 74 counterclockwise to initiate motion of the cambodies 70, 72 and 74 as described below.

Operation of device 10 begins with the cam bodies 70, 72 and 74 alignedas shown in FIG. 6 such that the regions of reduced radius 86 in the camsurfaces 76, 78 and 80 (see also FIG. 4 ) and gaps 102 in the tractionsurfaces 94, 96 and 98 simultaneously face the pinion axis 52. As shownin FIG. 1 , device 10 is mounted on tubes 132 extending from one end ofthe rotating chuck 12. The opening 46 in housing cover 18 faces thechuck 12 (see FIG. 2 ). Pinion axis 52 is coaxially aligned with theaxis of rotation 134 of chuck 12. A pipe element 136 is inserted intothe opposite end of the chuck 12 so that the end of the pipe elementextends outwardly from the chuck toward device 10. Chuck 12 is tightenedto secure the pipe element and the device 10 is then moved along tubes132 toward and into engagement with the pipe element.

With reference to FIGS. 2 and 4 , the pipe element passes throughopening 46 and into the central space 44. Aligned regions of reducedradius 86 and gaps 102 provide the clearance necessary to permit thepipe element to pass by cam surfaces 76, 78 and 80 and traction surfaces94, 96 and 98 to be received in the cup 68. The pipe element is thusaligned with the pinion axis 52. Device 10 is moved further toward chuck12 (see FIG. 1 ) so as to cause the pinion 48 to move axially along thepinion axis 52 and compress springs 66 sufficiently to move the crossbar 62 from the first to the second position out of the cut-out 64 inthe pinion bushing 54 (see FIG. 9A) to permit rotation of the pinion 48,and consequently rotation of gears 20, 22 and 24 which mesh with it. Thechuck 12 is then actuated, which rotates the pipe element clockwise asviewed in FIGS. 5 and 6 . Alternately, rotation of the pipe element canbe initiated and then the device 10 can be slid into engagement with thepipe element.

Engagement between the pipe element and the cup 68, when the cup is notfixed to the pinion, may cause the cup to rotate clockwise with thepipe. When the cup 68 is freewheeling relative to the pinion 48, thetorque transmitted via friction between the cup 68 and the pinion 48 maytry to rotate the pinion, and consequently gears 20, 22 and 24. Motionof the gears is easily prevented by engagement between the hook 118 andthe finger 120 extending from cam body 70 (gear 20). There isfurthermore no significant engagement between the pipe element and thecam bodies because the regions of reduced radius 86 in the cam surfaces76, 78 and 80 (see also FIG. 4 ) and gaps 102 in the traction surfaces94, 96 and 98 simultaneously face the pinion axis 52 and do notsignificantly contact the pipe at this time. If the cup 68 is fixedlyattached to the pinion 48 then engagement between hook 118 and finger120 again prevents motion of the gears and pinion, the pipe elementmerely rotates within the cup.

To initiate gear and cam body rotation, actuator lever 108 is depressed,causing it to pivot counterclockwise about its axis 108 a as viewed inFIG. 6 . As shown in FIG. 7 , pivoting of actuator lever 108 causes itsfirst surface 110 to engage the finger 112 extending from cam body 74,and also causes the foot 130 to engage the spur 128 of the hook 118.Hook 118 pivots clockwise about its axis 118 a and winds its biasingspring 126 (see also FIG. 2 ). The geometry of the actuator lever 108,hook 118 and its spur 128 is designed such that finger 120 on cam body70 is released from the hook 118 as torque is applied to rotate cam body74 via engagement of the first surface 110 of actuator lever 108 withfinger 112. FIG. 7 shows finger 120 on the verge of release from hook118 and cam body 74 just before engagement with the pipe element. Asshown in FIGS. 8 and 4 , further pivoting of the actuator lever 108pivots the hook 118 and releases the finger 120 from hook, (therebypermitting motion of the gear 20) while applying torque to the cam body74 (gear 24) to initiate rotation of the pinion 48 and gears 20, 22 and24 and their associated cam bodies 70, 72 and 74. The cam bodies rotatecounter clockwise and their cam surfaces 76, 78 and 80 and tractionsurfaces 94, 96 and 98 engage the outer surface of the pipe element. Thecam bodies 70, 72 and 74 are then driven by the rotating pipe element.The regions of increasing radius 82 (see FIG. 4A) of the cam surfaces76, 78 and 80 first engage the pipe element and begin to form acircumferential groove in it as the cam bodies 70, 72 and 74 rotate. Thetraction surfaces 94, 96 and 98 (see FIG. 4B) also engage the pipeelement and provide mechanical engagement which prevents slippagebetween the cam surfaces 76, 78 and 80 and the pipe element. As theradius at the point of contact between the cam surfaces and the pipeelement increases, the groove radius is made smaller until the point ofcontact transitions to the region of constant radius 84 (FIG. 4A) ofeach cam surface 76, 78 and 80. For a device 10 having three cam bodieswith respective regions of constant radius, each region of constantradius 84 extends over at least ⅓ of the circumference of the finishedcircumferential groove in the pipe element. The radius of the region ofconstant radius is designed to impart the final desired groove radius tothe circumferential groove in the pipe element at a uniform radiusaround the entire circumference of the pipe element with one revolutionof all three cam bodies. Alternately, when the regions of constantradius are not present on the cams, the groove radius is not uniform,but form separate partial spirals, one for each cam. Although notuniform, the radius of the groove falls within the necessary tolerancesfor the groove's intended use.

As shown in FIGS. 9 and 9A, cam body 74 nears completion of its singlerevolution and the finger 112 contacts the second (curved) surface 114of the actuator lever 108. Interaction between finger 112 and surface114 causes the actuator lever 108 to pivot clockwise about its pivotaxis 108 a and return to the starting position shown in FIG. 6 . Hook118 follows, biased by the spring 126 to pivot counterclockwise into aposition ready to receive the finger 120. When continued rotation of cambody 70 occurs it moves finger 120 into hook 118 which stops motion ofthe gears 20, 22 and 24. It is also feasible to design spring 126 tohave sufficient stiffness such that it will pivot both the hook 118 andthe actuator lever 108 back into the start position shown in FIG. 6 whenthe actuator lever is released. Upon completion of groove formation thechuck 12 is stopped and the pipe element, now grooved, may be removedfrom device 10.

FIGS. 10-12 illustrate an anomalous condition wherein the pipe elementis inadvertently rotated counterclockwise. This may happen due tooperator error, as power chucks such as the Ridgid 300 are capable ofapplying significant torque in both directions.

If reverse torque (i.e., torque which will rotate the pipe elementcounterclockwise as viewed in FIG. 10 ) is applied before the pipeelement has been grooved, the pipe element will merely rotate relativeto the cam bodies 70, 72 and 74 and their associated gears 20, 22 and 24because the regions of reduced radius 86 in the cam surfaces 76, 78 and80 (see also FIG. 4 ) and gaps 102 in the traction surfaces 94, 96 and98 simultaneously face the pinion axis 52 and thus neither surfacecontacts the pipe element. Additionally the ends of the regions ofreduced radius in the cam surfaces, being at the end of the region ofconstant radius 84, are too steep for the pipe element to climb throughfrictional contact even if the pipe element and the cam surfaces comeinto contact. Depressing the actuator lever 108 will have no significanteffect, as this action will try to rotate the cams and gears in theopposite direction from how the pipe element, rotating under reversetorque, will try to turn the cam bodies via friction between the cup 68and pinion 48 when the cup is not fixedly attached to the pinion.

However, if reverse torque is inadvertently applied after a pipe elementhas been grooved, the regions of constant radius 84 of the cam surfaces76, 78 and 80 are at approximately the same radius as the floor of thegroove and thus will gain purchase and rotate the cam bodies 70, 72 and74 clockwise. The torque on the cam bodies (and their associated gears20, 22 and 24) will be augmented when the pipe element further contactsthe traction surfaces 94, 96 and 98. As significant torque is applied tothe pipe element, measures are taken to prevent damage to the device 10.

FIGS. 10-12 illustrate the condition wherein reverse torque is appliedto a pipe element which has already been grooved. As shown in FIG. 10 ,the cam bodies 70, 72 and 74 are driven clockwise. The finger 120 on cambody 70 is moved away from the hook 118, but the finger 112 of cam body74 is driven against the actuator lever 108. Actuator lever 108 is freeto pivot clockwise in response to this applied force, the pivotingmotion allowing the finger 112 to fall off of the first surface 110 ofthe actuator lever 108 and engage the second (curved) surface 114,thereby avoiding any damage to device 10. As shown in FIG. 11 , the cambodies continue to rotate clockwise and the finger 120 of cam body 70comes into contact with the first of the two tangent surfaces 122 and124 on the end of hook 118. As shown in FIG. 12 , the first tangentsurface 122 is angularly oriented such that it permits the finger 120 topivot the hook 118 clockwise against its biasing spring 126 in responseto the force applied by the finger 120. Pivoting motion of the hook 118further prevents damage to the device 10. As the finger 120 transitionsto the second tangent surface 124 the hook 118 is permitted to pivotcounterclockwise under the force of its biasing spring 126 and moveagain to the ready position shown in FIG. 10 , as does the finger 112 oncam body 74. This motion will repeat until the motion of the pipeelement is stopped.

FIG. 13 shows another example embodiment of a device 138 according tothe invention having at most two gears 140, 142. Gears 140, 142 aremounted within a housing 144 for rotation about respective axes 146,148. A pinion 150 is mounted on housing 144 within a central space 152which receives a pipe element for processing. Pinion 150 meshes withgears 140, 142 and rotates about a pinion axis 154.

Cam bodies 156, 158 are respectively mounted on gears 140, 142. As shownin FIG. 14 , each cam body (156 shown) comprises a plurality of camsurfaces, in this example, two cam surfaces 160 and 162. Other camembodiments, including cams having a single cam surface or cams havingmore than two cam surfaces are also feasible. The cam surfaces 160 and162 extend around the respective cam bodies 156 and 158 and areengageable with the pipe element received within the central space 152.The cam surfaces 160 ad 162 are circumferentially aligned with oneanother. Each cam surface 160, 162 comprises a respective region ofincreasing radius 164 and a region of constant radius 166. The radii arerespectively measured about and from the axes of rotation 146 and 148.Respective regions of reduced radius 168, 170 are positioned betweeneach cam surface 160, 162 on each cam body 156, 158.

As further shown in FIG. 14 , a plurality of traction surfaces, in thisexample two traction surfaces 172, 174, extend around each cam body 156,158 (156 shown). Traction surfaces 172, 174 are circumferentiallyaligned with one another in this example. Traction surfaces 172, 174each comprise a plurality of projections 176 which extend transverselyto respective axes of rotation 146, 148. Respective gaps 178, 180 arepositioned between each traction surface 172, 174 on each cam body 156,158. Gaps 178, 180 are respectively aligned with regions of reducedradius 168, 170 in the cam surfaces 160, 162. As in the earlierdiscussed embodiment, the cam surfaces 160, 162 on each cam body 156,158 may be positioned, between the respective gears 140, 142 and thetraction surfaces 172, 174, and the cam surfaces may be locatedproximate to the traction surfaces on each cam body.

Cams having a plurality of cam surfaces and traction surfaces are sizedso that they form a complete circumferential groove for a fraction of arotation. For example, cams 182 as illustrated in FIGS. 13 and 14 havingat most two cam surfaces and two traction surfaces form a completecircumferential groove in one half a revolution of the cams.

Although devices having 2 and three cams are illustrated herein, designshaving more than three cams are advantageous for forming grooves havinga consistent radius, especially in pipe elements having a nominal pipesize of 2 inches or greater, or for pipe elements of any size having avariety of wall thicknesses.

FIG. 15 shows another embodiment 184 of a device for cold working pipes.Embodiment 184 comprises a housing 14 in which cams 69 (shown) or cams182 are rotatably mounted and mesh with a pinion 48. In this embodimentan electrical motor 186 is coupled to the pinion, either directly orthrough a gear box. In this arrangement it is advantageous if theelectrical motor 186 is a servomotor. A servomotor allows for precisecontrol of the number of revolutions of the cams 69 so that the regionsof reduced radius in the cam surfaces and the gaps in the tractionsurfaces are aligned at the beginning and end of the grooving procedureso that the pipe element can be inserted and removed easily. Control ofthe servomotor is effected using a programmable logic controller 188 orother similar microprocessor based computer.

FIG. 16 illustrates another device embodiment 190 wherein a clutch 192operates between the electrical motor 186 and the pinion 48. In thisexample, motor 186 is coupled to the clutch 192 through a reduction gear194. The clutch 192 engages the pinion 48 through a link chain shaftcoupling 196 which compensates for misalignment between the clutch andthe pinion. Clutch 192 is a wrapped spring type, examples of which arecommercially available from Inertia Dynamics of New Hartford, Conn.Wrapped spring clutches are readily adjustable to engage and disengageautomatically as needed to produce a desired number of revolutions ofpinion 48 to achieve a number of revolutions of the cams 69 required toform a circumferential groove and have the regions of reduced radius ofthe cam surfaces and gaps in the traction surfaces facing the pinion atthe end of the grooving process.

FIG. 17 illustrates another example device embodiment 198 wherein thedevice is supported directly on the pipe element 136 being cold worked.Pipe element 136 is, in turn, supported on a pipe vise 200 or otherconvenient support means which will prevent the pipe element fromturning when torque is applied about its axis 202. Device 198 issubstantially similar to device 10 described above, but has a crank 204coupled with the pinion 48 for manually turning the pinion, and therebygears 20, 22 and 24 and their associated cam bodies 70, 72, 74, camsurfaces 76, 78, 80 and traction surfaces 94, 96, 98 (see also FIG. 2 )to form a groove of uniform radius over the entire circumference of thepipe element 136. Crank 204 may be coupled to the pinion 48 by directlyengaging the pinion shaft 52 (a “direct” coupling between the crank andthe pinion), or a gear train (not shown) may be interposed between thecrank and the pinion shaft to reduce the torque required for manualoperation.

In operation (see FIGS. 2 and 17 ) the pipe element 136 is affixed tothe pipe vise 200 and the opening 46 in the cover 18 of the housing 14is aligned with the pipe axis 202. The opening 46 is then engaged withthe pipe element 136 and the housing 14 is slid onto the pipe element,which enters the central space 44 and is received within the cup 68 toseat the end of the pipe element 136 to the proper depth within thedevice 198 so that the groove is formed at the desired distance from theend of the pipe element. Optionally, to ensure proper pipe elementseating, device 198 may be equipped with the axially movable pinion 48as described above. When this feature is present the housing 14 isfurther forced toward the pipe element to move the pinion 48 axially anddisengage the cross bar 62 from the cut-out 64 to permit the pinion torotate relatively to the housing 14, thus ensuring proper seating of thepipe element 136 within device 198. Turning of the crank 204 will thenturn the pinion 48, which will turn the cams 69 through the gears 20, 22and 24 meshing with the pinion 48. Rotation of the gears engages the camsurfaces 76, 78 and 80 and the traction surfaces 94, 96 and 98 with thepipe element and the device 198 rotates about the pipe element 136 toform a circumferential groove of uniform radius. Upon one rotation ofthe cams 69 the groove is complete, and this condition is signaled tothe operator by an abrupt decrease in the torque required to turn thecrank 204. With the gaps 102 in the traction surfaces and the regions ofreduced radius 86 in the cam surfaces facing the pipe element 136,clearance is provided and the device 198 may be removed from the pipeelement. The grooved pipe element may then be removed from the vise 200.

Devices according to the invention are expected to operate effectivelyand cold work pipe elements to the desired dimensional tolerances withprecision while operating more quickly and simply without the need foroperator intervention.

What is claimed is:
 1. A device for cold working a pipe element, saiddevice comprising: a housing; a plurality of gears mounted within saidhousing, each one of said gears being rotatable about a respective oneof a plurality of axes of rotation, said gears being positioned about acentral space for receiving said pipe element; a plurality of cambodies, each said cam body mounted on a respective one of said gears; aplurality of cam surfaces, each one of said cam surfaces extendingaround a respective one of said cam bodies and being engageable withsaid pipe element received within said central space, each one of saidcam surfaces comprising a region of increasing radius and a region ofreduced radius; a pinion mounted within said central space within saidhousing, said pinion meshing with said plurality of gears and beingrotatable about a pinion axis.
 2. The device according to claim 1,wherein each of said cam surfaces further comprises a region of constantradius positioned adjacent to a respective one of said regions ofreduced radius.
 3. The device according to claim 1, wherein said regionsof reduced radius comprise respective discontinuities of said camsurfaces.
 4. The device according to claim 1, further comprising atleast one traction surface extending around one of said cam bodies, saidat least one traction surface comprising a plurality of projectionsextending transversely to said axis of rotation of said one cam body,said at least one traction surface having a gap therein, said gap beingaligned axially with said region of reduced radius of said cam surfacesurrounding said one cam body.
 5. The device according to claim 4,further comprising a plurality of said traction surfaces, each one ofsaid traction surfaces extending around a respective one of said cambodies, each one of said traction surfaces comprising a plurality ofsaid projections extending transversely to a respective one of said axesof rotation, each one of said traction surfaces having a gap therein,each said gap being aligned axially with a respective one of saidregions of reduced radius of one of said cam surfaces on each one ofsaid cam bodies.
 6. The device according to claim 1, wherein said atleast one traction surface overlies one of said cam surfaces.
 7. Thedevice according to claim 1, wherein said at least one traction surfaceis positioned on said one cam body in spaced relation to said camsurface extending around said one cam body.
 8. The device according toclaim 1, comprising at most, three said gears, each said gear comprisingone of said cam bodies and said cam surfaces.
 9. The device according toclaim 1, comprising at most, two said gears, each said gear comprisingone of said cam bodies and said cam surfaces.
 10. The device accordingto claim 4, wherein said one cam surface is positioned between said gearand said at least one traction surface of said one cam body.
 11. Thedevice according to claim 10, wherein said one cam surface is positionedproximate to said at least one traction surface of said one cam body.12. The device according to claim 1, further comprising at least oneprojection attached to said pinion, said at least one projectionextending transversely to said pinion axis; at least one cut-out definedby said housing, said at least one cut-out positioned in facing relationwith said projection; wherein said pinion is movable relatively to saidhousing along said pinion axis between a first position, wherein saidprojection engages said cut-out thereby preventing continuous rotationof said pinion, and a second position, wherein said projection is out ofengagement with said cut-out thereby permitting continuous rotation ofsaid pinion.
 13. The device according to claim 12, further comprising aspring acting between said pinion and said housing to bias said pinioninto said first position.
 14. The device according to claim 1, furthercomprising a cup abutting said pinion, said cup receiving said pipeelement upon insertion of said pipe element into said central space. 15.The device according to claim 14, wherein said cup is fixedly attachedto said pinion.
 16. The device according to claim 14, wherein said cupis free-wheeling relatively to said pinion.
 17. The device according toclaim 1, further comprising: a first finger extending from a first oneof said cam bodies in a direction offset from a first one of said axesof rotation about which said first one of said cam bodies rotates; anactuator movably mounted on said housing, said actuator being movableinto engagement with said first finger for rotating said first one ofsaid cam bodies about said first one of said axes of rotation.
 18. Thedevice according to claim 15, wherein said actuator comprises a leverpivotably mounted on said housing, said lever having a first surfaceengageable with said first finger for rotating said first one of saidcam bodies about said first one of said axes.
 19. The device accordingto claim 18, wherein said lever has a second surface engageable withsaid finger for pivoting said lever into a ready position upon rotationof said first one of said cam bodies.
 20. The device according to claim17, further comprising: a second finger extending from a second one ofsaid cam bodies in a direction offset from a second one of said axes ofrotation about which said second one of said cam bodies rotates; a stopmovably mounted on said housing, said stop being movable into engagementwith said second finger for preventing rotation of said second one ofsaid cam bodies about said second one of said axes of rotation; whereinupon movement of said actuator into engagement with said first finger,said stop further being movable out of engagement with said secondfinger for permitting rotation of said second one of said cam bodies.21. The device according to claim 20, wherein said stop comprises a hookpivotably mounted on said housing, said hook having a spur extendingtherefrom and engageable with said actuator for rotating said hook outof engagement with said second finger upon movement of said actuator.22. The device according to claim 1, further comprising a chuck forreceiving said pipe element, said chuck being rotatable about a chuckaxis, said chuck axis being arranged coaxially with said pinion axis.23. The device according to claim 22, wherein said housing is pivotablyand slidably mounted adjacent to said chuck.
 24. The device according toclaim 1, further comprising an electrical motor engaged with saidpinion.
 25. The device according to claim 24, wherein said electricalmotor comprises a servomotor, said device further comprising acontroller in communication with said servomotor for controlling thenumber of rotations of said servomotor and thereby said cam bodies. 26.The device according to claim 24, further comprising a clutch operatingbetween said electrical motor and said pinion for controlling the numberof rotations of said pinion and thereby said cam bodies.
 27. The deviceaccording to claim 1, further comprising a crank coupled with saidpinion, said crank for manually turning said pinion and thereby saidgears.
 28. The device according to claim 27, wherein said crank isdirectly coupled with said pinion.
 29. A device for cold working a pipeelement, said device comprising: a housing; a plurality of gears mountedwithin said housing, each one of said gears being rotatable about arespective one of a plurality of axes of rotation, said gears beingpositioned about a central space for receiving said pipe element; aplurality of cam bodies, each said cam body mounted on a respective oneof said gears; a plurality of cam surfaces extending around each saidcam body, each said cam surface comprising a region of reduced radiusand a region of increasing radius, said region of increasing radiusextending partially around said cam body and being engageable with saidpipe element received within said central space, all of said camsurfaces on each said cam body being circumferentially aligned with oneanother; a pinion mounted within said central space within said housing,said pinion meshing with said plurality of gears and being rotatableabout a pinion axis.
 30. The device according to claim 29, wherein saidregions of reduced radius comprise discontinuities of said cam surfacespositioned between each of said cam surfaces on each said cam body. 31.The device according to claim 29, wherein each of said cam surfacesfurther comprises a region of constant radius positioned adjacent to arespective one of said regions of reduced radius.
 32. The deviceaccording to claim 29, further comprising: a plurality of tractionsurfaces extending around each said cam body, each said traction surfacecomprising a plurality of projections extending transversely to one ofsaid axes of rotation; a respective gap in said traction surfaces beingpositioned between each of said traction surfaces on each said cam body,each said gap being aligned axially with one of said regions of reducedradius.
 33. The device according to claim 32, wherein said cam surfacesare positioned between said gear and said traction surfaces on each saidcam body.
 34. The device according to claim 32, wherein said camsurfaces are positioned proximate to said traction surfaces on each saidcam body.
 35. The device according to claim 29, wherein each of said cambodies comprises at most two of said cam surfaces and two of saidregions of reduced radius.
 36. The device according to claim 32, whereineach of said cam bodies comprises at most two of said cam surfaces, twoof said regions of reduced radius, two of said traction surfaces and twoof said gaps in said traction surfaces.